How to: Fabricate an occlusal guard
Using the Erkoform-3d unit and Erkoloc-pro to construct a hard-soft guard alternative.
Occlusal guards are the treatment for bruxism, clenching, as well as the treatment of temporomandibular joint discomfort. Debate has ensued as to whether the occlusal guard should be hard, soft or a combination of the two consistencies. Soft materials used for occlusal guards provide a more comfortable fit but are less wear resistant than their hard counterparts. They also, because of their resilient nature, may increase clenching activity due to their rebound effect when the patient occludes on them. Occlusal guards constructed of hard resins offer better wear resistance, prolonging the life of the guard, and eliminate the rebound effect seen with the softer materials. Unfortunately, they are not as comfortable to the patient when inserted or removed.
An alternative is a hard-soft occlusal guard. These offer the benefits of the soft guard, more comfortable to wear, insert and remove, with the benefits of the hard guard, better wear resistance and elimination of the rebound effect.
A 44-year-old female with moderate chronic clenching and bilateral TMJ popping on opening had an 8-year history of use of a mandibular occlusal guard. When she presented to the practice on initial consult, it was learned that her first occlusal guard was a soft material and lasted approximately two years before she wore through the material. Her complaint at the time was the “chewiness” of the guard made her feel like she had chewing gum in her mouth and was increasing the symptomology of the TMJ issues. A hard guard was fabricated and she successfully wore that for 6 years, until the posterior developed an occlusal crack on the right side.
During discussion with the patient regarding the need for a new occlusal guard, she expressed that she felt the hard guard she had been using had eliminated her increased chewing, but was difficult at times to insert and remove, and she felt that it was pressing on the teeth when worn. It was determined that a hard-soft occlusal guard would meet the patient’s desires and clinical needs.
Standard vacuform units are a challenge when using thicker plastic sheet materials and can be a greater challenge when using a dual laminate plastic. These units also tend to be weak in the vacuum (negative pressure) available during the forming portion of the technique. At the other end of the spectrum with regard to units for vacuforming are the pressure units. These require an airline be hooked to the unit and use positive pressure to form the plastics to the cast. They tend to be more complex and technique sensitive to fabricate occlusal guards, and as with the standard vacuform units, the user has to guess the temperature and time required for ideal use of the plastic material.
Glidewell’s Erkoform-3d is a self-contained, computerized “sudden vacuum” precharged chamber former that does not require an airline for operation (Fig. 1). It has a computer touchscreen that is preprogrammed for the various materials available to use in the unit.
After inserting the appropriate plastic into the holder, the user selects which material and plastic thickness is being used, and the unit sets the appropriate temperature and heating time, instructing the user when each step should be performed. The vacuum is activated automatically before the programmed temperature and time are reached, and the unit indicates to the user when it is ready to form the occlusal guard.
01. A study model is fabricated and the base is trimmed to eliminate any land areas at the vestibule. In the case of a lower cast, it is not necessary to eliminate the tongue area to create a “U” shaped case.
02. The cast is placed into the base of the Erkoform-3d and pressed into the metal shot, covering the base of the cast leaving only the portion of the cast to be captured exposed (Fig. 2).
03. A sheet of block-out material is placed over the shot beyond the cast to prevent the shot from sticking to the heated plastic during the forming process (Fig. 3).
04. The Erkoloc-pro material is placed into the holder with the soft side facing down. Each piece of Erkoloc-pro comes with a printed sheet of film covering the material, which is left on the piece until the forming is completed.
05. The unit is set for Erkoloc-pro in the thickness being used, and the process is initiated. When the unit indicates the material has reached its optimum temperature and time, the holder is swung over the cast and lightly pressed down (Fig. 4). The unit will go into cooling mode, and, after appropriate time, a signal is emitted indicating the occlusal guard is ready for removal from the unit and the finishing process can be started.
06. The formed guard and cast are removed from the unit (Fig. 5).
07. An electric knife may be used to outline the guard and remove the gross plastic and allow separation of the guard from the cast (Fig. 6). An alternative method is use of an acrylic bur or disk to make the preliminary cut. As it is common to damage the cast during removal of the guard from the cast, it is recommended that a duplicate cast be available (Fig. 7).
08. Using a Sharpie marker, a line is made indicating where the flanges should terminate (Fig. 8).
09. An acrylic bur (Brasseler USA) is used to trim back the flanges to the indicated line (Fig. 9). The printed film is removed from the guard. This is followed by contouring the flange edges with reticulated brushes (Dentsply Raintree Essix) sequentially progressing from coarse to fine. The reticulated brushes are used with very light pressure moving them with the edge of the flange to round the edges and eliminate any plastic fibers.
10. A rubber point (Brasseler USA) is used for final polishing, and a goat hair chamois brush (Brasseler USA) can be used as an adjunct for final polishing and is useful on any areas that require occlusal adjustment. This is used with very light pressure.
11. The guard is tried in on the duplicate case and fit and retention verified (Fig. 10). The hard-soft guard is now ready for delivery to the patient and occlusal adjustment if needed (Fig. 11).
As the material is a thermoplastic, the patient should be advised not to place the guard in hot water as this will cause distortion of the guard. The guard may be cleaned with traditional denture cleaners or scrubbed with a toothbrush and nonabrasive toothpaste with cold water.
It is generally agreed that patients with parafunctional habits such as clenching and bruxing do benefit from occlusal guard therapy. But if the occlusal guard is uncomfortable, the patient’s compliance will be poor.
The Erkoform-3d unit combined with the Erkoloc-pro dual laminate occlusal guard material permits quick and easy fabrication of a hard-soft occlusal guard in the dental office. This technique can be accomplished at minimal cost and time.
About the author
Gregori M. Kurtzman, DDS, MAGD, DICOI, is in private general practice in Silver Spring, Md. He can be reached via e-mail at [email protected].